'Fed up with weapons'

Some 6,000 Lou Nuer warriors descended on the Pibor district to attack the Murle in retaliation for a deadly raid last August.

The UN has been unable to verify the number of deaths, but survivors spoke of seeing hundreds of bodies after scorched-earth attacks in which villages were burnt to the ground.

Some 80,000 heads of cattle taken from Murle areas by the men, the UN says.

"The people of Jonglei are fed up with these weapons," South Sudan's military spokesman, Philip Aguer, told the BBC's Focus on Africa programme about the disarmament operation.

"We are not expecting resistance, but if anyone fires at the army, that is a different story," he said.

Last week, the UN warned that disarmament may increase tensions in the state.

"Jonglei's rival communities are wary of relinquishing their weapons, regardless of government promises to carry out disarmament simultaneously in each area," the UN Office for the Co-ordination of Humanitarian Affairs said in a statement.

Water well destroyed

Image caption
Cattle are a central part of the lives of many communities in South Sudan

The BBC's James Copnall in Khartoum says South Sudan's first months as a new country have not been easy.

Cattle vendettas are common in many regions as are other clashes between rival groups.

But our reporter says it is especially in its relations with Sudan that tensions have been most fraught.

The two are locked in a bitter row over oil, with the south shutting down production after accusing Khartoum of stealing some of it.

On Thursday, South Sudan accused its northern neighbour of dropping bombs on Panakuat, near the border.

Mr Aguer told the BBC he believed there had been casualties but he did not have precise details.

He said the bombs dropped from two planes destroyed a water well, and also hit oil installations.

Oil has leaked into a water source, depriving a village of drinking water, he said.

South Sudan believes it was a deliberate attempt to target the oil wells.

Our correspondent says Panakuat is near the part of South Kordofan in Sudan where rebels are fighting the Sudanese government.

Khartoum accuses South Sudan of supporting those rebels, and also of sending troops into region to fight the Sudanese army, which Juba denies.